The fuel systems of air breathing engines can generally be divided into two distinct categories. In one category, the fuel is sprayed out of one or more jets into an area generally at a pressure somewhat less than ambient. A typical example of an engine utilizing this approach is a carbureted internal combustion engine.
In a second category, high pressure fuel injectors may be utilized, the high pressure being useful in atomizing the fuel as it emanates from a nozzle. Typical examples of this approach include direct injection diesel engines and virtually all gas turbine engines.
In the case of the latter, gas turbines use high pressure injection into the combustion chamber primary combustion zone in order to obtain the desired or required fuel ratio that is necessary to sustain stable, efficient combustion.
In the usual case, gas turbine engines utilize a source of pressurized fuel along with a plurality of discrete injectors to spray and atomize the fuel into the combustion chamber at high pressure. Fuel pumps are required to operate over a wide range of fuel flows and with varying suction conditions. Frequently, they may require boosting or multiple stages.
Not infrequently, the use of such high pressure systems will represent a fairly high percentage of the total cost of an engine. For example, it would not be surprising to those skilled in the art that the cost of fuel pumps, injectors, manifolds and associated metering controls could constitute as much as 25% of the total cost of the gas turbine engine.
The present invention is directed to overcoming one or more of the above problems.